Pneumatic power-hammer.



A. BERNER.

PNEUMATIC POWER HAMMER.

APBLIOATION FILED APR. 13. 1909.

9Q,163 Patented DecQ'Y, 1909.

4 SHEETS-SHEET 1 y Pm [7 m A. BERNER. PNEUMATIC POWER HAMMER.

APP LIQATION FILED APR. 13, 1909. 92, 1 88 v Patented Dec. 7, 1909.

4 SHEETS-SHEET 2.

A. BERNER. PNEUMATIC POWER HAMMER. APPLIOATION FILED APK.13, 1909.

942,163. Patented Dec. 7, 190

' 4SHEETSSHBBT 3 azmm' A. BERNER.

Patented Dec. 7, 1909.

4 SHEETSSHBET 4.

PNEUMATIC POWER HAMMER. APPLICATION FILED APR. 13, 1909.

, showing the valves Unrr . AUGUST BERIlEIt, 0F MUNICH, GERYJEANY.

application To all whom it ma/y concern: I

Be 1t known that 1, license: Brianna, sub- 'ect of the German Emperor, residing at unich, Germany, have invented new and useful Improvements in Pneumatic Power ll'animers, of which the following is a specr fication. I

This invention relates to apneumatlc hsnr mer with two cylinders (a pump and a ran; cylinder), the endsv of which are connected by passages with one another. In the known forms ofconstruction of such harnmers it is necessary in order togovern the working tool as completely and certainly as possible, that each of the two passages connecting the pump drawings.

Fig. 1 and Figs. 5+7 show a vertical-section' oi the hammer made throu h'the middle'ofi', cylinders and slide va ve in various positions of the slide valve; while l i 2 is a vertical section of the slide valve mat e at right angles to the central plane of the two cylinders; Figs. 2 and 5 are views similar to Figs. 2 and 5 respectively, but 'in different positions. Figs. 3 and 4 are two sections on an enlargod scale. made atright angles to one another of the governing slide valve.

As appears from the drawings the pneu Jnatic hammer has a pump cylinder a and a cylinders, which passages lead to eslide from the under an ram cylinder 1) separate therefrom; in these cylm ers the pum plstonc and the ram piston 41 which in its upper part is hollow,

are respectively arranged in such a Way that on both ends of the pistons working chambers e and f and g and, h respectively are formed. Passe es 2', is, Z, m, branch oil upper working chambers c, g, and f, h, respectively of the two valve ar 'a-nged between h'hth cylinders and located on an inserted bush a. For the purpose of shortenmg the slide valve as far as specification of Kietters Patent.

serial Flo. 469,706.

possible, said passages extend to nearly middle of the valvccylinder before opening into it.

The pump piston is formed as a stepped piston ant-1' rovided with a hollow trunk or piston re p which is guided in a stufiing. be}: 5 The upper annular extension of this" Patented lliec. *3, j

stun ing box g enters the lower part of the pump cylinder a, leaving an annular space (3 between it and the walls of the said e e .mder a and is provided wlth apertures' or' ports 1" distributed around its periphery, which. ports are uncovered by the hollow piston rod p when the map piston 'ap preaches the upper end 0 lts stroke. This arran nnent of the holes 7" in the extension idling cox projecting into the puirip allows of piston rings being eflecftively employed on the hollow piston rod '39,

a: any connection of the openings 9 with the e do are ct oi Ward stroke.

air is excluded as soon they by the piston I'Ul' S on the down The pumpcy inder has also a deflecting passage .2 which branches 0a near the cylinder cover and comaects again with the cyln'ider chamber at a distance from its starting point approximately "cor-'- responding to the thickness of the piston. In consetpience of this arrangement there lsalways an atmospheric pressure established at the cornmcmcment of the downward? movement of the camp piston, both 111% the suction chamber over the upper piston sur'--- face and also in the pressure ehainoerunder the lower piston ring surface, and thereby a uniform worlnnp oi the hammer is produced. The ram cyinidcr Z) is provided with a passage 6 forming a eentinuation of the passa e m, which passage-Z passes through the cy inder cover and con-= nects with the rain cylinder co-axially with the former. The pass-aged passes 11 word into the lubricating passage connecte with a lubricating vessel it placed above and 'isprovided with a nonretur'n' valve 1) only:

opening; inward. In the wall of the ram' cylinder Z) a passage w is also provided,

7 which branches oil at a distance from the cylinder cover, which corresponds with'thedepth of-the piston hollow and connects again with thecylinder at a distance from its branching point, coinciding with the height of the piston. At this endof the passage a non-return valve :0 is provided, which is adapted to open ,only under the in, the. valve casing.

superpressure reigning in the working chamber g.

The governing slide valve 0 consists preferably of a cylindrical body and 1s traversed by two passages y a of elongated rounded section, the ends-of which are enlarged and the central axes of which extend at a distance from one another corresponding to the distance of the'mouths of the assages i, l, and is, m, respectively formed in the valve cylinder. The recess lying to the left of the passage .2 merges into the lateral recess 4 lying on the right hand side of the slide valve-0 and extending downward, by the intermediaryof open1ngs3 adapted to be closed by the non-return valve 2, which recess 4 at its lowerend is continuediintoa perforation 5 leading beyond the middle of the slide and running in the same direction as thepassages y 2. From this perforation 5 a passage 7 branchesoft, which as. regards its dlameter coincides with the perforation 5, and is arranged transversely to the latter, which passage 7 at its end extends into a recess or enlargement 8 widening downward. At the rear side of the. slide valve casing Fig. 2, a perforation '9 leads to-the outside, which is also closed by a valve 10 opening inward only. A pipe 11 (Fig. 2) connecting with the interior of the ram cylinder is also connected with the valve casing, which pipe by the displacement of the slide valve may be laced in communication'with the open air y means of a passage 12 which crosses it transversely" and an aperture 13 provided The slide valve has in addition-a small passage 6 which also connects with the outside and which may be connected with the passage 70 of the ram cylinder.

The pump piston is operated in known manner by-meansof a rocking crank gear 14, 15, while for displacing the distributing valve a lever mechanism- 17 18, 19, pivotal on a fixed pin 16 is provided. "If regular heavy blows are to be given, the distribut ing slide valve is so adjusted that the central axes of its ports .y a coincide with the centers of the mouths of the connecting passages i is and Z m (Fig. 1) which months are situated in the valve casing. I

The hammer described works as follows When the pump piston is at the up er end of its stroke the ports 0" of the stu ng box are uncovered by the hollow piston rod 7),

so that there isatmospheric pressure in the working chamber e and also, by the arrangement of the passage .9, in the working cha1nber f. After a small downward movement of the pump piston these ports rare covered by the piston rod,' .so that inthe lower pump chamber 6 there is compression, but in the upper chamber f a partial vacuum, and the ram piston, in consequence of the connection of the working chambers g h of the ram cylinder with those of the pump cylinder, is lifted. As a partial vacuum is formed in the working chamber It Over the ram cylinder, the ram piston d is thrown upward until it is close to the cover, under the action of the effective pressure on. its under side, and the momentum imparted to it, until there is produced there the necessary compression for forming an air cushion. The recoil resulting therefrom would, however, be too hard and under certain circumstances even dangerous. avoid this drawback and to obtain a sutficiently efl'ective air cushion the side passage w is provided, the non-return valve m of which is opened as soon as the lower edge of the piston has passed over its mouth.

In order to Compressed air then flows through this pas- .reached the lower end of its stroke, it again rises, so that expansion of the air and a diminution of pressure takesplace in'the lower working chambers e and g" of the pump and 'ram cylinders respectivel and the ram can drop freely. This talling movement is assisted .by thev expansion of the previously compressed air cushion above the ram piston at. As soon as the pump piston again approaches the upper end of its stroke,-the ports 1' are again uncovered and' atmospheric pressure is again reestablished above'and below the pump piston.

For the purpose of giving light blows, the slide valve is displaced upward in such a way that the passage Z is placed in communication with the outer air through the passage 3 of the slide valve and the pipe 11 coinciding withthe transverse perforation or port 12 of the slide valve (Fig. By this means on the one hand the suction action produced by the working chamber f relative to the ram piston is considerably diminished, while on the other hand the compressed air expelled from the working chamber 6 and which operates the lifting of the ram piston, escapes from the working chamber 9 as soon as the lower edge of the ram piston has passed the mouthof'the pipe 11. Consequently the ram piston does not rise to its entire height of lift'and the suction action on the same for the downward movement only again takes place when it has again covered themouthof the pipe 11.. If the ram is to be kept raised, the slide valve is displaced so much farther upward that the central axis of the non-return valve I 2 lies about at the same height as the mouth of thep'assages z Z2, and the connecting passage Z 15 in direct, communication with the external air by the intermediary of the passage y of the slide valve and the recesses.

provided at its ends. The recess 8 at theend wer of the passage 7 ol the slide valvohas also moved in froiit of the opening 90f the valve mounted on the slide vaiyc casing. in

consequence pf tliis" p( sition of the slide valve no suction action is eXei'ted. on the upper end of the rain piston by the reciprocating pump piston. yj-"bn the pump piston a rising, however, fresh air is always drawn through the valve 10 and the passages 9, 8, 7 5, 4, 2, into theworlnng'chamber e, which a r is compressed on the descent of the pump piston and forced into the working chamber. 1 under the ram cylinder. In order to depress the ram, a further displacement of the distributing slide valve is efiecte'd by the lower-edge of the passage G-being turned. with respect to that of the passage is and the passage 2 carrying in its lower recess the pressure valve 2, being brought into communication Withthe passage m of the ram cylinder 7). In the upward movement of the pump piston, similarly to when therein. is held up a'ir is drawn throughtlie valve 10 and the passages 9, 8i, 7', 5, 4, fl into the working chamber 6. On the descent of the pump piston on the other hand the compressed air is forced into the. Working? chamber '72 through the passages 2', 3:2, m. As air also escapes from the Working chamber 9' into the open through the passage 6 on the movement of'the pump piston, and. this es- I cape of air only takes place slowly, the ram is gently placed on theworkpiece and then firmly pressedithereon.

It is of essential importance both in the holding' up as Well as the depression of the rain, that the pressure action should take place in both cases merely at the lower annw lar face of the pump piston. it is thereby rendered possible to produce a considerably higher pressure on the rams when they rest {on the workpiece ina position of repose,

than if the upper face of the pump pistonproduced the pressure on the ram, and the I expenditure oipower by the hainmei is re duced because in this case only the annular face of the pump piston act-s under pressure, whereas if the same pressurewas employed against the much larger upper face of the pump piston the effect would be much re .duced. In order to prevent too grezit an increase of the pressure, a safety valve 20 is provided at the end of the Working chain her 6, through which valve the wmpressed air blows oil as soon as the pressure attains a height which is inadmissible for practical I declare that what I claim is 1; In a pneumatic hammer, a pump cylinder, and a striding her. cylinder of smaller diameter engaging one end of the pump cylinder, in combination, with a stepped piston fitting into the cylinder one end and having a trunk adapted'to slide'iiitlie stufing nor: cylinder,

tting in and Y euirl stuiling box cylinder lacing novidcd witli a commumcalion leading, into the annular space between the pump cylinder and thepistonlruulguud arranged at a point here it will be exposed when the pump piston arrives near the end of its forward stroke, a commiinication between the head of the pump cylinder space and an iutcrnnv diate portion of said cylinder space, adapted to be opened by the piston near the end ct its forward stroke 2. in a pncun'iatic hammer, a pump cylinder having a communicating pa age bctween its head and an intcrn'iediatc portion, and a stuliing box cylinder of smaller diameter engaging the end of the pump cylinder, extending a short distance within the same to form an annular space with the said pump cylinder, and provided with a series of ports extending from the interitir of the saidstuiiing cylinder into the said annular and a casing containing a valve device for controlling the conmmnication between the,

pump and the mm, in combination, with e ductconuecting an intermediate part of the rain cylinder .with the valve casing, and a port in the valve device; adapted to register with said. duct, when tile valve device has been shifted into the proper position.

4. in. a pneumatic hammer, an air corn pressing pump, a rain cylinder, a ram piston adapted to reciprocate within the same, and a valve cylinder arranged between the two and having ports for thecommunica tion between theforward and rear portionsof the cylinder-spews of the ump cylinder and the ram cylinder, in corn ina'tion, with a duct leading from an intenuoiliate portion of the ram cylinder into the valve cylinder, and' a slide valve slidehly arranged Within the yalve cylinder and provided with communicating passages adapted to reglster "with the ports of the same and. w th a transverse passage leading to the exterior and, adapted to register with the said duct, whereby the ram piston may he raised only to a portion of its stroke. I

5. ln a pneumatic hammer, a ram cylinder, in comhii'iation, with a ram piston adapted to reciprocate Within the same, and

ueans for introducingcompressed into i the rear part of the cylmtler,'tlie said cyi-' upper and lower cylinder spaces of the inder being provided with a passage conin' 'an air cushion atithe headof the cyI necting the head 3 f the forward working in er.

'chamber with an ntermediate portion of In testimony whereof I have signed my the cylinder space; a non-return valve being name to this speclficatlon 1n the presence 5 arranged in the said passage and so disof two snbscriblng witnesses.

posed that the compressed air .will be allowed to pass forward into the eylindei AUGUST head, when the piston ,has passed the Witnesses:

rear opening of said passage, but will'be ABRAHAM .ScHLEsINGEm 10 prevented from ,returnmg, thereby p roduc- LoUIs I. MUELLER. 

